Apparatus for making pneumatic inner tubes



F. T. ROBERTS. l

APPARATUS FOR MAKING PNEUMATIC INNERv TUBES.

APPLlcAnoN 111.511 SEPT-15, 1919.

1,387,6 1 6. Patented Aug. 16, 1921.

2 SHEETS-SHEET l:

A TTORNEY,

F. T. ROBERTS., APPARATUS Foa MAKING PNEuNAnc INNER TUBES.

APPLICATION FILED SEPT-1511919. y l 1,387,61 6. Patented Aug. 16, 1921.

2 SHEETS-SHEET 2.

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.UNITED'STATES PATENT OFFICE.

rmiD THOMAS ROBERTS, oroLnvnLAND, OHIO, AssreNOR To PARAMOUNT RUBBERCONSOLIDATED, moz, or Y DELAWARE. n

`PHIL A])LLPI'IIA,` PENNSYLVANIA, A CORPORATION OF AyPAnATUs FOR MAKINGrNnuMATIoINNER TUBES.

for example, inner tubes for pneumatic tires.`

It is desirable to form articlesof this character of two pieces ofrubber stock joined by peripheral vulcanized seams, thus doing away withthe stretching `and buckling which I kresults when a straight tube isformed into an annulus and obviating the leakage frequently consequentupon securing the over- 'lapped ends by cement.

The present apparatus is designed to hold annular rubber stool; upon theces of mold:

members and pneum'aticallvseatr such stock in annular channels in themold members and join theL parts of the seated stock tc f gether toproduce the complete article with the peripheral seams. The invention ishere` inafter described'more in detail in connection with theaccompanying drawings and the essential novel characteristics arefsetont in the claims.

` YIn the drawings, Figure l. is a transverse section through a pair` ofmold members and a su1table press vfor bringing them into congunction.Fig. 2 is a plan of one of the mold members; Fig, 3 is a verticalsection on vproduced bythe molds of Figs. l and 4;

Fig. 6 isa cross-section of an inner tube in 'a tire casing, the tubebeingY shown in solid lines as inflated and indicated by brokenV linesin its uninfiated condition.

Describingthe parts by the use of re-'r1 erence numerals, 1 and 2indicate thevupper and lower'mold members, which are sub1,

Specification of Letters Patent.

` ofthe main channel and a yPatented Aug. 16|, 1921.

Application inea september 15, 1919. seriai'No. 323,851.

stantially identical, and in each of which is formed the annular channel3 corresponding to the shape of half of the article as joined. Y

These mold members are preferably in the nature of'large plates and theymay be secured by any suitable means to lstationary and movable platens5 and 6 of a. suitable press (Fig'l) the lower platen being adapted` tobe raised into co-action by a plunger 7 in the cylinder 8, by meansl ofliquid forced through a pipe lO under the control of a valve 9.

The rubber'sheets are placed across the molds and are seated in theannular channels'by pneumatic pressure, preferably suction. For suchsuction'to be effective it is `important that the sheet on the innerkand outer sides ofthe channel be held to the mold. To enable suchholding I provide annular grooves I5 and 16 immediately in* side andoutside of the edges of the channel,

v and supply suction to these grooves so that the rubber sheet isclamped to the face of the mold. v

It is lconvenient to connect the annular grooves mentioned and the mainchannelV With one source of suction, and to this ond 18` and i9 With themain channel and the grooves l5 and 16, and I provide a suction pipe 20in connection With space i7.

Fig. 3 shows rubber stoclr S after it has been seated by suction in theclamping grooves and the' mainchannel. Between these grooves and channelare similar cuttinged ges l2 so formed that when tivo mold membersare'brought together, as shown in 3, the stock is sheared off at theedge. peripheral seam is formed.-

In making inner tubes and similar annular articles 'which have a fillingnipple,

it desirable to place the'nipple between two pieces of stock after,Vthey are seated in their channels and before they are brought intoconjunction. 'To provide for this, I make fin each of the nioldmembers 1and 2, a radial passageway 22 which extends from f the channel to the`inner edge of the mold member. This radiall channel has on its oppositel'sides parallel cutting ribs 23. The time@ radial @beveel .bridge overthe has been seated, as shown in the case o1' the lower mold member inFig. 1, the nipple having a washer P and sleeve Q, is placed in thestock which has been seated in the channel 22 by reason oisuctionthroughthe opening fr nut R on the nipple and an adjacent washer V may bearagainst the inner edgeot the mold member and thus cause Y the washerv Vto seat firmly against the rub- Vso ber stock seated in the mold. Theinner edge of the annular rubber sheet, when the stock is seated, ispractically coterniinous with the inner periphery o1" the mold so thatthe stock extends across the length of the channel 22.

This is `et such length that the sleeve portion termed by the twochannels 22 houses the sleeve Q on the nipple. New when the moldmembersare brought together 'by the operation of the plunger 7, thisbrings the cutting edges 12 together to'shear ott the stock and formperipheral seams. At the same time the cutting edges 23 cut off thestock along the opposite sides of the nipple and seam them togetheraround the sleeve Q.

A. convenient method of using the molds described, is to place annularrubber sheets (such as shown at S bene-ath the upper mold in Fig. 1)over the mold cavities, bringing the edge of the sheet downwardly toclose the grooves 15 and 16, whereupon the vacuum passages may beopened, thus tightly drawing the edge oli the rubber into these groovesand, in effect, pneumatically clamping the' same over the surface of themold members and across the mold channels. A continued application ofatmospheric pressure by reason of vacuum within the chamber forces therubber into the channels (as vslunvn in the lower mold ot' Fig. 1) therubber lying closely in contact with the mold surface.

The mold members may now be brought forcibly together, bringing thecutting edges 12 into contact, severing the rubber around the channel,the excess merely being forced into the space beyond the raised cuttingedges .as indicated in Fig. 5. i

Before bringing the molds together, suitableexpansible material suchA asammonia powder may be deposited on the rubber within the cavity so thatsubsequent heatingmay cause expansion fot `the article into theV closecontact with the wall of the vulcanized mold cavity in La well knownmanner, or the molds may bebrought vtogether in an atmosphere ofcompressed air, entrapping such compressed air therein, which mayprovide the desired internal oressure tor vulcanization.

fitter the molds have been brought together severing the articles withintherehannel 'from 4the exterior and interior portions oi1 the sheet,these articles may be removed and placed in channels SO'formed in sepa-'able mold members 31 and 32, comprising the vulcanizing molds. Thesevulcanizing molds may conveniently be made et stamped metal; in use theyare suitably secured t0- `get-her by means not shown.l fr suitableradial ljnissage (not shown) provides for the housing of the nipple.rllhus an innerftube such as shown at 'il in Fig. 5 may be pro-` duced.Y

To reduce the depth and consequent cost ot the molds, as well as toprovide for a more uultorm thickness et wall of the tube asnnuiulactured, l arrange the mold channels as shown in the drawings, sothat they have a crossesection which adjacent tothe edge is asubstantially circular arch extending downwardly at 2i" and then curvedinwardlyto an inward annu-lar protuberance 26. When the the centralportion of the stock engages the surface of the protuberance before suchregion of the stock is stretched to a greater extent than the stoel;adjacent to the edges ot' the mold. Further stretchingY into the easycurve by which the sides of the channel merge with the centralzonestretches the rubber but slightly more, with a result that when the artc e is vforced completely to its seat, it is or thickness throughout.

il n inner tube of the peculiar `iorm shown in Figs and G, namely;having a crosssection which is an elongated loop with a contractedwaist, has advantages over an ordinary tube. `@ne advantage is that thetube in v be readily put in place through a comparatively narrow openingat the inner edge ett a tire casing. Y r'inother at vantage is that thetube is materially smaller when ina-de than when inflated, resultingin asaving ot rubber. i can make it smaller because the form shown allowsthe stretch to occur at the sides where it does no harm, withoutmateriallyY thinning the tread portion, where t richness is desired.` ltis obvious, however, that the apparatus may be employed for making innertubes which do not have this ieculiar ,orm, as well as for making otherannular articles.

This' application' is a continuation in part of my co-pendingapplication No. 154,072 filed March 12, 1917 (now Patent No. 1,346,848issued July 20, 1920), which shows an annular suction cavity embraced byannular raised cutting edges and provided with an annular suctionclamping grooveu Attention also should be called tomy corubber is drawninto such a mold,

substantially the sameY llt) *12, 1918, fora mold for making hollowrubber articles, as that application contains broad claims on asuctionalclamping groove associated with'a mold cavity.

1. 1n anl apparatus ofthe character described,-the combination of apair'of co` operating mold fmembers each having a single-.cavity and'each having an annular clamping groove surrounding the cavity,

and means for applying' suction lto,l said groove, f

2. Inan'apparatus ofthe character de-A scribed, the combination of amold meniber having a single cavity and having an annular clampinggroove surrounding the rcavity, and means for applying Asuction tothecavity and groove.

3. The combination inra mold of acavity, two grooves on oppositesides-of the cavity 'frespectively, and `means' for applyingV suction tosaid grooves;

4. The combination ofva mold' member having an annular mold channeland'two grooves on opposite sides of the channel `re i"spectively,`andmeans Vfor applying suction to saidfgroovesi y 5'. The* combination of amold Amember having an annular mold channel and two grooves onoppositesides of the channelre` 'spectively, and means Vfor simultaneouslyapplying suctio moldniember's, each having an annular mold 'f'fchanneland two grooveson opposite sides i' @said grooves. f

ofthechannel` respectively, means for ap-V plying suction to saidgrooves and' to ythe annular channel, and means for'thereafter bringingthe mold ymembers into conjunction. f *7, lThe combination of V'a 1moldmember` having an annular mold channel, two raised cutting edges onopposite-sides of the channel respectively, groovesbeyond the cuttingedges and means 4for applying'` suc-tion to :8. The combination [of a;mold member having an annular channel and an inwardly extending lradialchannel communicating` with said annular channel and means for apf"plying suction to the-annular channel.

nto said grooves and tothe annular channel. 1 l v n 6. The combinationof arpairl of coacting nular clamping grooves beyond the cutting g edge,

12. An apparatus for making pneumatic inner tubes comprising a pair ofmold plates, each having annular channelswith cutting edges about theirinner and outer periphery, and a lateral channel intersecting the cutting edge of the inner periphery. i

13. An apparatus for making pneumatic inner tubes comprising a pair ofmold plates, each having annular channels with cutting edges about theirinner and outer periphery, and a radial channel intersecting the cuttingedge of the inner periphery, and cutting edges on opposite sides of theradial channel.

14. An apparatus for making pneumatic inner tubes comprising a pair ofmold plates, each having annular channels with cutting edges about theirinner and outer periphery, a radial channel intersecting the cuttingedge of the inner periphery, and means for applying suction to saidannular channel.

i5. A inner tubes comprising a pair of mold plates,

each having annular channels with' cutting n apparatus for makingpneumatic' sides-of the channel respectively,a lateral channelcommunicating with the channel mentioned' and crossing one of saidgrooves, and means for applying suction to said grooves'.

17. The combination of a mold member having an annular channel with anannular protuberance in its base, a suction chamber, and passageway fromsaid chamber to low points ofsaid channel on opposite sides of saidprotuberance.

V18. In an apparatus for manufacturing rubber tire tubes, thecombination of two mold members adapted to coact and each `having anannular groove in its face, said groove being' formed withuan annularprotuberance in its base, and means for applying a superior pneumaticpressure to the outer face of rubber stock placed to bridge across thecavity'. y

9. In an apparatus for manufacturing rubber tire tubes, the combinationof two mold members adapted Ato coact and each having an annular groovein its face, said groove being formed with an annular protuberance inits base, and means for applying suction to the cavity, enabling theformation of a tube with inwardly bowed sides.

20. in an .apparatus for manufacturing rubber tire tubes, thecombination of two mold members adapted Ato coact and each having anannular groove in its face, said groove being formed Vwith an annularprotuberance in its` base, and annular' ribs forming` cutting edges'onthe faces of the molds about the inner andaouter edge of the annulargrooves.

2l. A mold for making hollow rubber articles having a cavity with araised cutting edge adjacent to it and means for exhausting air fromsaid cavity.V`

.in apparatus for making. hollow rubber articles, a mold having acavityand a raised cutting edge surrounding cavity and a passageway leadingfrom the cavity.

In apparatus for making hollow rub: ber articles, the combination ofcooperating mold members each having a cavity and a raised cutting edgesurrounding` cavity and means for exhausting air from the cavity.

24. The combination of a pair of moldV members each having a cavity forforming a portion of the article, cutting edges surroundingthe cavitiesand adapted to cooperate with each other to form a periph- Y eral seamabout the article and cut off the surplus stock, and means forexhausting air lfrom the cavities to seat rubber stock of exhausting airfrom the cavities to seat the stock, and means for bringing the moldmembers together to form a peripheral seam.

26. In an apparatus of the class deu scribed, the combination of a moldpress having a pair of platens, one of which is movable, a pair ofco-acting molds adapted y,to be mounted against the respective platens,said molds having cavities opposite each other and each having a raisedcutting edge adjacent to the edge of the cavity, said raised cuttingedges on the two molds cooperating to effect the seam and cut offsurplus stock when the molds are brought together, and means forapplying suction to vthe two cavities. l

27. In an apparatus of the class described, the combination of a moldpress having a pair of platens, one of which is movable, a pair ofcoacting molds adapted to be mounted against the respective platens,said molds having cavities opposite each other and each having a raisedcutting edge advraised cutting edge surrounding each cavitv at its outeredge, said cutting adges on the twomolds being opposite each 4other andadapted to form a peripheral seam on the article when the two molds arebrought together, and means for exhausting air from the two cavities. l

30. A mold for making hollow rubber articles having an annular cavity, araised cutting edgeadjacent to the outer edge of the cavity, and apassageway leading from the cavity. K Y

3l. A combination of a pair of co-acting mold members each having acavity and a pair of cutting edges on. opposite sides of the cavity,respectively, and means for eX- hausting airfrom the cavities.

32. A mold for making hollow rubber an- Vnular articles comprising amember having an annular cavity therein, raised cuttingV edgesadjacentrespectively to the inner and outer edges of the cavity, and apassageway leading from the cavity.

33. ln an apparatus of the class described, the combination of a pairofco-acting mold members, each having an annular cavity therein and raisedcutting edges located respectively adjacent to the inner and outer edgesof the cavity, means for applying suction tothe two cavities, and meansfor bringing the mold members together.

34. ln an apparatus of the class described, the combination of a pair ofco-acting mold members, each having an annular cavity therein and raisedcutting edges loc-ated respectively adjacent to the inner and outeredges of the cavity, means for bringing the mold members together, andsuction pipes connected with the two molds,-one of the molds beingmovable and the pipe connected therewith being flexible.

in testimony whereof, I hereunto afix my signature.

FRED THOMAS ROBERTS.

